Research
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I am broadly interested in the structure of pelagic ecosystems and the behavior and physiology of the organisms within them. My research has considered pelagic food webs as model systems to investigate linkages between animal movements, ecology, and physiology, as well as for applied studies that inform more sensible ecosystem management.
I am open to diverse questions and research techniques, which has allowed for timely responses to emergent problems and information gaps. However, several consistent project themes unify most of my previous and current research.
I am open to diverse questions and research techniques, which has allowed for timely responses to emergent problems and information gaps. However, several consistent project themes unify most of my previous and current research.
Projects
Pelagic Ecosystem Structure.
Open ocean ecosystems comprise a large portion of the world's natural habitat and support massive fisheries. Improving ecosystem management and predicting the ecological impacts of anthropogenic change can only be accomplished with a firm understanding of food web dynamics. My approaches have been question-dependent, and I have applied a diverse suite of techniques tailored to best address data gaps for a given species or system. Methodologies have included bulk stable isotope analysis, amino acid-compound specific isotopic analysis, electronic tagging, molecular techniques, and mercury analysis. Several of these studies have demonstrated the value of predators as 'bio-samplers' in pelagic systems, providing access to a diverse assemblage of cryptic taxa more effectively than traditional sampling methods.
Open ocean ecosystems comprise a large portion of the world's natural habitat and support massive fisheries. Improving ecosystem management and predicting the ecological impacts of anthropogenic change can only be accomplished with a firm understanding of food web dynamics. My approaches have been question-dependent, and I have applied a diverse suite of techniques tailored to best address data gaps for a given species or system. Methodologies have included bulk stable isotope analysis, amino acid-compound specific isotopic analysis, electronic tagging, molecular techniques, and mercury analysis. Several of these studies have demonstrated the value of predators as 'bio-samplers' in pelagic systems, providing access to a diverse assemblage of cryptic taxa more effectively than traditional sampling methods.
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Relevant publications
Madigan DJ, Carlisle AB, Dewar H, Snodgrass OE, Litvin SY, Micheli F & BA Block. 2012. Stable isotope analysis challenges wasp-waist food web assumptions in an upwelling pelagic ecosystem. Scientific Reports.
Madigan DJ, Carlisle AB, Gardner LD, Jayasundara N, Micheli F, Schaefer KM, Fuller DW & BA Block. 2015. Assessing niche width of endothermic fish from genes to ecosystem. Proceedings of the National Academy of Sciences.
Carlisle AB, Goldman KJ, Litvin SY, Madigan DJ, Bigman JS, Swithenbank AM, Kline Jr TC & BA Block. 2015. Stable isotope analysis of salmon shark vertebrae reveals ontogenetic changes in habitat in a pelagic shark. Proceedings of the Royal Society B.
Tsai F-Y, Chiang W-C, Chen C-C, Madigan DJ & Y-S Ho. 2016. Feeding ecology of dolphinfish (Coryphaena hippurus) in the waters off eastern Taiwan. Journal of Taiwan Fisheries Research.
Madigan DJ, Chiang W-C, Wallsgrove N, Popp BN, Kitagawa T, Choy A, Tallmon J, Ahmed N, Fisher NS & C-L Sun. 2016. Intrinsic tracers reveal recent foraging ecology of Pacific bluefin tuna at their primary spawning grounds. Marine Ecology Progress Series.
Madigan DJ, Carlisle AB, Dewar H, Snodgrass OE, Litvin SY, Micheli F & BA Block. 2012. Stable isotope analysis challenges wasp-waist food web assumptions in an upwelling pelagic ecosystem. Scientific Reports.
Madigan DJ, Carlisle AB, Gardner LD, Jayasundara N, Micheli F, Schaefer KM, Fuller DW & BA Block. 2015. Assessing niche width of endothermic fish from genes to ecosystem. Proceedings of the National Academy of Sciences.
Carlisle AB, Goldman KJ, Litvin SY, Madigan DJ, Bigman JS, Swithenbank AM, Kline Jr TC & BA Block. 2015. Stable isotope analysis of salmon shark vertebrae reveals ontogenetic changes in habitat in a pelagic shark. Proceedings of the Royal Society B.
Tsai F-Y, Chiang W-C, Chen C-C, Madigan DJ & Y-S Ho. 2016. Feeding ecology of dolphinfish (Coryphaena hippurus) in the waters off eastern Taiwan. Journal of Taiwan Fisheries Research.
Madigan DJ, Chiang W-C, Wallsgrove N, Popp BN, Kitagawa T, Choy A, Tallmon J, Ahmed N, Fisher NS & C-L Sun. 2016. Intrinsic tracers reveal recent foraging ecology of Pacific bluefin tuna at their primary spawning grounds. Marine Ecology Progress Series.
Dynamics and Ecology of Basin-Scale Migrations.
Long distance migrations are a fundamental life history trait of many pelagic and coastal species. The underlying oceanographic and ecological drivers of many of these migrations are poorly understood, hindering the ability to forecast the effects of changing oceans on the distribution and foraging of marine predators. In some cases, the spatiotemporal dynamics of migrations are not adequately understood for regional, and sometimes international, management efforts. Colleagues and I have used SIA, AA-CSIA, radionuclides, otolith microchemistry, conventional tagging, and electronic tagging techniques to better understand the migration of pelagic species and the foundational ecology behind these movements. In some cases, anthropogenic influences have been apparent in both movements and regional foraging patterns.
Long distance migrations are a fundamental life history trait of many pelagic and coastal species. The underlying oceanographic and ecological drivers of many of these migrations are poorly understood, hindering the ability to forecast the effects of changing oceans on the distribution and foraging of marine predators. In some cases, the spatiotemporal dynamics of migrations are not adequately understood for regional, and sometimes international, management efforts. Colleagues and I have used SIA, AA-CSIA, radionuclides, otolith microchemistry, conventional tagging, and electronic tagging techniques to better understand the migration of pelagic species and the foundational ecology behind these movements. In some cases, anthropogenic influences have been apparent in both movements and regional foraging patterns.
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Relevant Publications
Madigan DJ, Baumann Z, Carlisle AB, Snodgrass OE, Dewar H & NS Fisher. 2017. Isotopic insights into migration patterns of Pacific bluefin tuna in the eastern Pacific Ocean. Canadian Journal of Fisheries & Aquatic Sciences.
Madigan DJ, Brooks EJ, Bond ME, Gelsleichter J, Howey LA, Abercrombie DL, Brooks A & DD Chapman. 2015. Diet shift and associated site fidelity of oceanic whitetip sharks (Carcharhinus longimanus) along the edge of the Great Bahama Bank. Marine Ecology Progress Series.
Baumann H, Wells RJD, Rooker JR, Zhang S, Baumann Z, Madigan DJ, Dewar H, Snodgrass OE & NS Fisher. 2015. Combining otolith microstructure and trace elemental analyses to infer the arrival of juvenile Pacific bluefin tuna to the California Current Ecosystem. ICES Journal of Marine Science.
Madigan DJ. 2015. Understanding bluefin migration using intrinsic tracers in tissues. In T Kitagawa & S Kimura (eds), Biology & Ecology of Bluefin Tuna. Boca Raton, FL: CRC Press.
Carlisle AB, Goldman KJ, Litvin SY, Madigan DJ, Bigman JS, Swithenbank AM, Kline Jr TC & BA Block. 2015. Stable isotope analysis of salmon shark vertebrae reveals ontogenetic changes in habitat in a pelagic shark. Proceedings of the Royal Society B.
Madigan DJ, Baumann Z, Carlisle AB, Hoen DK, Popp BN, Dewar H, Snodgrass OE, Block BA & NS Fisher. 2014. Reconstructing trans-oceanic migration patterns of Pacific bluefin tuna using a chemical tracer toolbox. Ecology.
Madigan DJ, Baumann Z & NS Fisher. 2012. Pacific bluefin tuna transport Fukushima-derived radionuclides from Japan to California. Proceedings of the National Academy of Sciences.
Carlisle AB, Kim SL, Semmens BX, Madigan DJ, Jorgensen SJ, Perle CR, Anderson SD, Chapple TK, Kanive PE & BA Block. 2012. Using stable isotope analysis to understand migration and trophic ecology of northeastern Pacific white sharks (Carcharodon carcharias). PLoS ONE.
Madigan DJ, Baumann Z, Carlisle AB, Snodgrass OE, Dewar H & NS Fisher. 2017. Isotopic insights into migration patterns of Pacific bluefin tuna in the eastern Pacific Ocean. Canadian Journal of Fisheries & Aquatic Sciences.
Madigan DJ, Brooks EJ, Bond ME, Gelsleichter J, Howey LA, Abercrombie DL, Brooks A & DD Chapman. 2015. Diet shift and associated site fidelity of oceanic whitetip sharks (Carcharhinus longimanus) along the edge of the Great Bahama Bank. Marine Ecology Progress Series.
Baumann H, Wells RJD, Rooker JR, Zhang S, Baumann Z, Madigan DJ, Dewar H, Snodgrass OE & NS Fisher. 2015. Combining otolith microstructure and trace elemental analyses to infer the arrival of juvenile Pacific bluefin tuna to the California Current Ecosystem. ICES Journal of Marine Science.
Madigan DJ. 2015. Understanding bluefin migration using intrinsic tracers in tissues. In T Kitagawa & S Kimura (eds), Biology & Ecology of Bluefin Tuna. Boca Raton, FL: CRC Press.
Carlisle AB, Goldman KJ, Litvin SY, Madigan DJ, Bigman JS, Swithenbank AM, Kline Jr TC & BA Block. 2015. Stable isotope analysis of salmon shark vertebrae reveals ontogenetic changes in habitat in a pelagic shark. Proceedings of the Royal Society B.
Madigan DJ, Baumann Z, Carlisle AB, Hoen DK, Popp BN, Dewar H, Snodgrass OE, Block BA & NS Fisher. 2014. Reconstructing trans-oceanic migration patterns of Pacific bluefin tuna using a chemical tracer toolbox. Ecology.
Madigan DJ, Baumann Z & NS Fisher. 2012. Pacific bluefin tuna transport Fukushima-derived radionuclides from Japan to California. Proceedings of the National Academy of Sciences.
Carlisle AB, Kim SL, Semmens BX, Madigan DJ, Jorgensen SJ, Perle CR, Anderson SD, Chapple TK, Kanive PE & BA Block. 2012. Using stable isotope analysis to understand migration and trophic ecology of northeastern Pacific white sharks (Carcharodon carcharias). PLoS ONE.
Development of Chemical Tracer Techniques.
Chemical tracers can act as intrinsic markers of animal movement and diet, incorporating regional and trophic signals over integrated timeframes. As such, tissue-bound tracers can provide retrospective life history information for harvested animals and/or cryptic lifestages. However, these tracers often must be calibrated or ground-truthed using captive and/or wild data; this can be especially important for large pelagic fish, which often lack laboratory-controlled data due to the difficulty of captive rearing. We have developed methodology and/or biological parameters for multiple chemical tracers in pelagic fish, which can then be applied to wild data from ecologically/physiologically similar species.
Chemical tracers can act as intrinsic markers of animal movement and diet, incorporating regional and trophic signals over integrated timeframes. As such, tissue-bound tracers can provide retrospective life history information for harvested animals and/or cryptic lifestages. However, these tracers often must be calibrated or ground-truthed using captive and/or wild data; this can be especially important for large pelagic fish, which often lack laboratory-controlled data due to the difficulty of captive rearing. We have developed methodology and/or biological parameters for multiple chemical tracers in pelagic fish, which can then be applied to wild data from ecologically/physiologically similar species.
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Relevant Publications
Madigan DJ, Baumann Z, Snodgrass OE, Ergul HA, Dewar H & NS Fisher. 2013. Radiocesium in Pacific bluefin tuna Thunnus orientalis in 2012 validates new tracer technique. Environmental Science & Technology.
Madigan DJ, Baumann Z & NS Fisher. 2012. Pacific bluefin tuna transport Fukushima-derived radionuclides from Japan to California. Proceedings of the National Academy of Sciences.
Madigan DJ, Litvin SY, Popp BN, Carlisle AB, Farwell CJ & BA Block. 2012. Turnover rates and fractionation of carbon and nitrogen isotopes in an endothermic teleost, Pacific bluefin tuna (Thunnus orientalis). PLoS ONE.
Kwon SY, Blum JD, Madigan DJ, Block BA & BN Popp. Quantifying mercury isotope dynamics in a captive pelagic fish, Pacific bluefin tuna (Thunnus orientalis). Elementa: Science of the Anthropocene.
Bradley CJ, Madigan DJ, Block BA & BN Popp. 2014. Amino acid incorporation and enrichment factors in Pacific bluefin tuna, Thunnus orientalis. PLoS ONE.
Shipley ON, Brooks EJ, Madigan DJ, Sweeting CJ & RD Grubbs. 2017. Stable isotope analysis in deep-sea chondrichthyans: recent challenges, ecological insights, and future directions. Reviews in Fish Biology & Fisheries.
Carlisle AB, Litvin SY, Madigan DJ, Lyons K, Bigman J, Ibarra M & JJ Bizarro. 2016. Interactive effects of urea and lipid content confound stable isotope results in elasmobranchs. Canadian Journal of Fisheries & Aquatic Sciences.
Madigan DJ, Baumann Z, Snodgrass OE, Ergul HA, Dewar H & NS Fisher. 2013. Radiocesium in Pacific bluefin tuna Thunnus orientalis in 2012 validates new tracer technique. Environmental Science & Technology.
Madigan DJ, Baumann Z & NS Fisher. 2012. Pacific bluefin tuna transport Fukushima-derived radionuclides from Japan to California. Proceedings of the National Academy of Sciences.
Madigan DJ, Litvin SY, Popp BN, Carlisle AB, Farwell CJ & BA Block. 2012. Turnover rates and fractionation of carbon and nitrogen isotopes in an endothermic teleost, Pacific bluefin tuna (Thunnus orientalis). PLoS ONE.
Kwon SY, Blum JD, Madigan DJ, Block BA & BN Popp. Quantifying mercury isotope dynamics in a captive pelagic fish, Pacific bluefin tuna (Thunnus orientalis). Elementa: Science of the Anthropocene.
Bradley CJ, Madigan DJ, Block BA & BN Popp. 2014. Amino acid incorporation and enrichment factors in Pacific bluefin tuna, Thunnus orientalis. PLoS ONE.
Shipley ON, Brooks EJ, Madigan DJ, Sweeting CJ & RD Grubbs. 2017. Stable isotope analysis in deep-sea chondrichthyans: recent challenges, ecological insights, and future directions. Reviews in Fish Biology & Fisheries.
Carlisle AB, Litvin SY, Madigan DJ, Lyons K, Bigman J, Ibarra M & JJ Bizarro. 2016. Interactive effects of urea and lipid content confound stable isotope results in elasmobranchs. Canadian Journal of Fisheries & Aquatic Sciences.
